Synchronizing system



F. w. MEYER SYNCHRONIZING SYSTEM Filed Dec. 8. 1924 4 Sheets-Sheet 1 3 ,2 2 KB l 'TT/ehtor Z Friedrich \X/. Meyer, 9 His Attohney.

July 3 1926. 1,592,611

F. W. MEYER SYNCHRONIZING SYSTEM Filed Dec. 8. 1924 4 Sheets-Sheet 2 w. MEYER SYNCHRONIZING SYSTEM Filed Dec. 8,1924 4 Sheets-Sheet 5- Fig.7:

fiver-to? 2 Friedrich Me er,

His Aoclcmvac-2 July 13 1926.

1,592,611 F. w. MEYER swcunozuzme SYSTEM- Filed Deo. 8. 1924 4 Sheets-Sheet 4 Fig. 8.

Irv/enter- I Friedrich W Meyer,

9 His Attorney.

l frequency,

. SlOl1 of an Patented July 13, 1926.

UNITED STATES PATENT OFFICE.

rammncn WILHELM sierra, or BRUNSWICK, enmnmmssronoa r0 GENERAL nnncrmc comrm, a coaropa'rron or new YORK.

; smcnn'omzmo srs'rnm.

lpplication flled December 8, 1924, Serial No. 754,517, and in Germany November 15 1921.

My invention relates to systems for interconnectin two electric power sources or systems w on they are in phase and operat ing at substantially the same voltage and and has for its object the proviimproved synchronizing system which is capable of being'operated automatically to interconnect two systems when a predetermined relation has been established between their electrical conditions, or at a predetermined time before or after such a relation has been established? A state of synchronism between two power lines or systems may be considered to exist when they are in phase and operating at the same voltage and frequency. In the past, various arrangements have been proposed. and used for determining when a state of synchronism between two power systems has been established. Many of these arrangements involve the use of dash pots or too many auxlliary moving mechanical masses and are not altogether satisfactory in their operation for the reason that. they do not always respond in exactly the same manner to the establishment of a given relation between the electrical conditions of the systems to be interconnected. In accordance with my invention, these ditliculties I are largely avoided by the use of electron discharge devices which are arranged to causeoperatlon of a synchronizing switch when a cond tion. of synchronlsm between the systems has been established; As explained hereinafter, the use of electron dis: charge devices in this connection is of particular. advantage in that the use of 'moving mechanical parts is for, the most part avoided and in that a very accurate and re liable determination of the time interval between the establishment of a predeter mined relation between the electrical conditions of the different systems and interconnection of the systems is renderedlpo'ssible."

My invention will be better understood from the following description when considered in connection'with the accompalfky ing drawing and its scope will be poin out in the appended claims.

Figs. 1 and-'2 show arrangements which.

comprise an electron discharge device interconnected with "a reactor and a resistor ina manner to produce closure of a switch in 1 response to the transmission of current of a predetermined frequency and which may rent sources or systems in response to a pre-' determined a relation bet-ween the electrical conditions of the two sources or systems; Fig. 4 shows an arrangement which differs from that of Fig; 3 in certain of its details; Fig. 5 shows an arrangement which is op erable to interconnect two sources or systems when a predetermined relation exists between their voltages and which may form one element of a complete synchronizing system; .Figs. 6 and 8 show a complete synchronizing system wherein electron discharge devices are utilized in combination with electromagnetic devices for the purpose of interconnecting two systems automatically when they are substantially in phase and operating at substantially the same voltage and frequency; and Fig. 7 showsa complete switchlng or synchronizing system in which only electron discharge devices are utilized to produce interconnection of two lines or systems when they are in phase and operating at substantially the same voltage f at which current is transmitted through a circuit. In this arrangement, 7 current for energizing the operating coil 2 of the switch 1 is supplied from" a suitable source shown as a battery 3 through an electron disa receptacle 4, an

charge device comprisin anode 5, a cathode 6 an a grid 7. A battery Sand an adjustable resistor 9 are provided for controlling the temperature of the cathode 6. It will of course be understood that any suitable means may be provided for ensuring an adequate supply of electrons at the cathode 6., The control or grid circuit of the electron discharge device comprises a reactor 10 which is connected in series with the resistor 11 across a reactor 12 through which is transmlttedi It will be readily understood that a voltage drop will be produced across the reactor 12 when alternating current is transmitted the alternating current through and that, assuming the amplitude electron discharge device only when the voltage impressed on its control circuit through the reactor '10 attains a predetermined positive value. Thus, assuming current to be transmitted through the reactor 12' and line 13 at a comparatively low frequency, the voltage impressed on the-reactor 10 and resistor 11 will be comparatively low, a very considerable portion of this voltage drop will appear at the terminals of the resistor.

11 due to the fact that the rate of change in the current value is low, and the voltagev impressed on the grid 7 through the reactor lO-will be -insuflicient to cause operation of the switch 1. As the frequency of the current is raised however, the voltage drop across the reactor 12 will increase, the proportion of the voltage drop appearing at terminals of the reactor 10 will increase due to theincrease in the rate at which the value of the current changes, and eventually a value of grid voltage .will be reached at which suflicient current will be transmitted through the electron discharge device to produce operation of the switch 1. The reactor 10 and the resistor 11 thus serve to magnify or amplify the effect of the voltage drop across the reactor 12 upon the grid circuit of. the electron discharge device. For the purpose of simplifying the drawing, the electron discharge device has been shown as arranged to rectify but one side of the voltage wave impressed on the reactor 10. It will be apparent however,

that this device must usually be arranged ,ina well known manner to rectify both sides of the wave, since otherwise the current pulsations would be separated by time intervals sufficiently long to permit operap t1on of the. switch. In any given case the nected in series. In this arrangement, the

resistor 17 is connected across the. control circuit of the electron discharge device.

With these connections, the voltage drop across the resistor 17 will increase as the frequency of the constant voltage line 14-15 decreases until eventually a, value of grid voltage is reached at Which operation of the switch 1 is produced. In the operation of this arrangement closure of the 21, and through reactor 22 and resistor 23.:

With these connections, the' sum of the system voltages is impressed on the cross connection formed by the resistor 20 and reactor 21. It will be observed that the resistor 20 also forms a part of a circuit 'comprising the resistor'24c and the reactor 25 which are provided foramplifying the ef feet of the voltage drop across the resistor 20 on the grid or control circuit of the electron discharge device.

The magnitude of the voltage drop across the resistor 20 is determined to some extent by the phase and voltage relations existing between the two systemsand to some extent by the frequency relations existing between the systems. 111$,lfffih6 systems are in phase, the sum of their voltages is impressed on the reactor 21 and the resistor. 20. The proportion of this voltage sum available at the terminals of the resistor 20, however, is dependent on the, resultant frequency of the twosystems. Thus, assuming the frequency of the system 19 to be normal and to remain constant and that of thesystem 18 to be high, the voltage drop across the reactor 21 will also be high. As the frequency of the I system 18 approaches that of the system 19 however, thevoltage drop acrossthe reactor 21 which is the sum of two equal voltages produced by the current waves of systems 18 and 19 decreases, system 18 having now attained the same frequency as system 19 and the resultant frequency having become.

zero. onsequently, the drop across the resistor '20 increases to a value which ought to be deciding for the action of the switch. This point, however, is the correct switching: point only if the phaseis correct. If A the phase is not correct, the voltage drop is less than the aforesaid value. herefore, both with-regard to phase .and frequency, there @will; be a voltage drop left from the corresponding relays if the real switching point is not attained. Both differences have the same sense. The diiference produced from phase difference has a, maximum and this maximum becomes sharper with de- I creasing frequency ,up to the switching point. When bringing the system 18 upto synchronism With the system 19 instead of raseaen down to synchronism with this" stem a similar condition can be attained i the reactor 21 is connected across the series connected resistor 24 and reactor 25 instead ofthe resistor 20.,

The eifect of the resultant frequency onthe voltage applied to the grid 7 is further eters ,or other mechanical devices formerly used for this purpose.

Fig. .4 shows an arrangement which differs from that of Fig. 3 in that the two systems are cross-connected through resistors 28 and 29 and in that an adjustable part of the voltage drop of the resistor 29' is applied to the control circuit of the electron dlS- charge device through a resistor 26 and a 0 condenser 27. In" the operation of this em rangement, the sum of the system voltages is impressed on the resistor 29 and all adjustable part of this voltage sum is applied to the circuit formed by the series-connected resistor 26 and condenser 27. The proportion of the voltage sum applied to the control circuit of the electron discharge device is to some extent determined by the re" sultant frequency of the two systems for the reason that thp voltage drop across the condenser 27 becomes larger as the value of the resultant frequency decreases. Disregarding the efi'e'ct of the. condenser 27, the onlyfactor in producing maximum potential of the control circuit. and operation of the switch, however, would be the phase relation of the systems.

Fig. 5 shows an arrangement'for ensuring the proper relation between the voltages of the sources 18 and 19 before closure of the switch 1 by which their interconnection is eflected' In this arrangement, the voltage of the source 18 is applied to the resistor 30 through a transformer 31 and a rectifier 32 which mav comprise a heated cathode 33,

and the voltage of the source 19 is applied to the resistor 34 through a transformer 35 and a rectifier 36. It will be observed that the resistors 30 and 34 are interconnected through a conductor 37 so that the differ ence of their voltage drops is impressed on the resistor 38 which is connected across the condenser 27 and resistor 26. I

In the operation of the arrangement 'shownin Fig. 5, the voltage drop across the resistor 38 and consequently the potential of the grid 7 is determined by the resultant difference between the voltages of. the two sources. Assuming the potential of the grid to be positive, theswitch 1 willbe maintained in open position'when a considerable difference between the voltages of the two sources exists; As this difference in voltage decreases, however,'the grid potential will be correspondingly reduced and will eventually assume a value at which operation of the switch 1 is produced, the current pulsations ofthe rectifier circuits being smoothed out by the condenser 27. It will be apparent that the arrangement of Fig. 5. may form a component part of a complete synchronizing system, and may thus be utilized to favor interconnection of the systems when their voltages are equal.

The synchronizing system-shown by Fig. 6 differs from those previously described in that an electro-dynamic device 42 of well known construction "is arranged to beoperated at a speed proportional to the resultant frequency of the power lines 43'and 44 for the purpose of causing interconnection of these lines (through a switch 45' only when the frequencies of the two lines are very nearly the same. The stator windings 46, 47 and "48 of the machine 42 are connected between the conductors of the lines- 43 and 42 and its rotor 49 is mechanically coupled to a small dynamo electric machine 50 through the shaft 51. With these connections the machine 50 will be driven at a speed dependent on the resultant frequency of thetwo systems and, assuming constant excitation, 1ts voltage will be a measure of this resultant frequency. It will be observed that in this case the influence of the system frequencies per se is obviated and an effect dependent entirely upon the resultant frequency is produced.

It will be observed that the operating coil 52 of the switch 45 is arranged to be supplied with current from a battery 53 throu h switches 54, 55 and 150. Operation of t e switch 54 is produced throughan electron discharge device comprising a cathode 55", an anode 56, and a grid 57. A battery 58 is connected in the plate or operating circuit of the electron discharge device for maintaining the switch 54 in its open 7 ition while the potential of the grid 57 is comparatively high. 'As the magnitude of the resultant frequency of the lines 43 and 44 decreases, however, the speed and voltage of the machine 50 will decrease until eventually the potential of the grid 57 is reduced to a point at which closure of the switch 54 is efi'ected.

Operation of the switch 55 is produced through an electron discharge device comprising anodes 59, cathodes 60 and grids 61.

A .battery 62 is connected in the plate.

or op rating pdircuit of this electron discharge device for maintaining the switch 55' in its open position while the potentials of the grids T61 are comparatlvely high. The potentials of the grids 61 are determined by the voltage drop across a resistor 63 which is connected between the corresponding terminals of the-syste'm conductors. With this arrangement the difierence of the system voltages is impressed on the resistor 63. When the voltages of these conductors are unequal in magnitude, or out of phase with one another, a voltage drop will be produced across the transformer 63 through the resistor 63 and ,the switch 55 will be maintained in its open position. As the voltages of these conductors approach equality and come into closer phase relation.-

. 2'0 ship, however, the. potential of the grid 61 will decrease until the conductor voltages have substantially the same .value and phase when closure of the switch 55 will occur. Closure of the switch 45 is therefore possible only-when. the lines-43 and 44 are in phase and operating at substantially the same voltage.

Operationof the switch 150 is produced throu'gha disk 151 which is mounted on the shaft 51 and an electron discharge device which, comprises a cathode 153, a grid 154 and an anode 155 Current for operatingtheswitch 150 is supplied to its operating coil 156 from a battery 157 which is connected in the operating circuit of the electron dischar e device. The grid or control circuit of this device is arranged to be connected to the battery 158 through the. disk 151 which is provided with-brushes159 and 160 and with an insulation segment 161.

Theoperation of the control apparatus of switch 150 will be readily underst0od.when

resultant requency is high, the time intervals during which the circuit between the battery 158 and the grid 154 is interrupted will be too short to permit closure of the switch, but as the resultant frequency decreasesm value, the grid circuit will be interruptedwfor longer and longer intervals until eventually the switch 150 is caused to close. Closure of the switch 45 can thus efi'ected only when the two systems are m phase 7. and operating at substantially the 7 same voltage and frequency. As indicated above the operation of the switch 55 vis dependent on both the phase and voltage relations existing between the two systems. The provision of the switch 150 therefore is an additional factor in producing closure of election discharge devices are concatenated for the purpose of producing prompt and definite action of the switches through which interconnection of thelines is efifected. In

this system, the lines 66 and 67 are arranged to be interconnected through a switch 68 which is provided with an operating coil 69 arranged to be supplied with current from a battery 70' through the switches 71, 72 and 73. As hereinafter explained, the switch 71 is arranged to be operated to its closed position when the frequencies of the lines 66 and 67 become substantially the same, the switch 7 2 is arranged to be operated when the voltages of the two lines are substantially equal in, magnitude and the switch 73 is arranged to be closed when the two lines are in phase with one another.

Operation of the switch 71 is produced through an electron discharge device 74 which comprises a-cathode 75, anodes 76 and 77, and grids 78 and 7 9. Reactors 80 and 81, which are connected between the corresponding conductors of the lines 66 and 67 in series with the resistors 82, and 83, and resistors 82' and 83', which'may be'alike, are arranged to complete the high impedance connection between the'systems 66 and 67, are rovided for controlling the potentials of t e grids 78 and 79 respectively in accordance with the resultant-frequency of the lines 66 and 67.. Batteries 84; and 85 are arranged to be connected in the plate circuits of the device 7 4. Assuming that the frequenc of the system 67 is constant and that the requency of the system 66 is approaching that of the system 67, the resultant frequency of the lines 66 and 67 will decrease to zero as the frequencies of these lines approach equality, the resultant voltagedrop across the reactors 80 and 81 and the potentials of the grids 78 and 79 will likewise decrease, due to the fact that the voltage drops produced by the current waves of the two systems have become equal and their resultant has become zero so that closure of the switch 71 will be roduced. While the resultant frequency 0 the two systems is the main factor so far con nseam;

sidered in producing closure of the switch 71, it will be apparent that operation of this switch is also influenced more or less by the phase and voltage relations of the two systerns, and that in some cases the device 74 may be of itself suflicient to produce closure of the switch 68 at the proper'instant if all these influences are brought out properly.

Operation of the switch 72 is produced through the electron discharge devices 89 and 90. The device 89is arranged to have its anodes 91 and 92 connected to the lines 66 and 67 through transformers 93 and 94 respectively and is provided with a cathode 95. The midpoints of'the secondary windings of the transformers 93 and 94 are connected to opposite ends of a resistor 96 which has its midpoint connected to the cathode 95. With these connections, the voltages of the lines 66 and 67 are rectified and their resultant difference is impressed on the resistor 96. So long as the voltages of the lines 66 and 67 are of unequal magnitude therefore a voltage drop will be produced across the resistor 96.

The electron discharge device 90 comprises cathodes 97 and 98, anodes 99 and 100, and grids 101 and 102. .Batteries'103 and 104 are provided in the plate circuits'of the electron discharge device 90 for controlling the energization of the switch operating coils 105 and 106 of the switch 72 in accordance with the potentials of the grids 1 01 and 102. The potentials'of the grids 101 and 102 are determined by-the voltage drop across the resistor 96 which, as explained above, is dependent on the difference between the"mag nitudes of the two line voltages. It will be readily understood that as the difference between line voltages decreases, the potentials of the grids 101 and 102 will decrease until eventually the coils 105 and 106 are deenergized to a point at which closure of the switch 72 is produced.

Operation of the switch 73 is produced through electron discharge devices 107, 108 and 108'. The anodes 109 and. 110 of the device 107 are arranged to be connected to the lines 66 and 67 respectively through transformers 111 and 112, and comprise cathodes 113 and 114 which are shown as separated by a partition 115. The midpoint of the secondary winding of the transformer 111 is connected to the cathode 113 through a-resistor 116, the midpoint of the second ary winding of the transformer 112 is like wise connected to the cathode 114: through a resistor 117, and the left hand ends of the resistors 116 and 117 are interconnected through a conductor 118. With these connections, a voltage proportional in value to the'resultant of the rectified system voltages is produced between the right hand terminals of the resistors 116 and 117. The right hand end of the resistor 116 is connected to the cathode 127. The right hand end of the resistor 117 is interconnected with'the grid 125 through conductor 119, system 67, resistor 83', system 66 and conductor 120. The potential of thegrid 125' is therefore determined by the resultant of the rectified system voltages and theactual system voltages. When this resultant voltage is positive in value, suflicient current. is supplied from a battery 130 to an operating coil 132 of the'switch 73 to maintain this switch in its open position. When this resultant voltage has become zero or has a small negative value, the current is interrupted or greatly reduced in value and the .coil 132 is rendered incapableof maintaining the switch 132 hits open position.

Closure of the switch 73 during the interval of time when the other half waves 'allow switching is favored by the operating coil 133 which is arranged to be supplied with current from a source 131 through anode 124' and cathode 128 of the device 108. For the purpose ofcausing the grid 126 to have a zero potential iithe other half waves give correct switching points an electron discharge device 108' is connected to the systems 66 and 67 through the transformers 111' and 112' and is arranged to produce voltage drops in resistors 116 and 117 which are proportional in value to the rectified voltages. The design and connections of the device 108 are in all res ect similar to the design and connections 0 the device 107 except that connections between the grid 126 and cathode 128.a-re reversed with respect to the connections between the grid 125 and cathode 127. The grid 126 is 00.nnected to the cathode 128 through resistors 117 and 116, conductor 119, system 67, re

sistor 83', .system 66 and conductor 120. With these connections, the reversed resultant voltage will be applied to the grids 125 and 126 and the switch 73 will be inaintained in its open position either by the coil 132 or the coil 133 until the resultant voltage has decreased to a value which permits it to close.

The fact that the potentials of grids 125 and 126 are obtained bybalancing the rectified system voltages against the actual system voltages is of advantage for the reason that these potentials are rendered independent of differences in the ma nitude of the system voltages and closure 0 the switch 73 is ensured at a time when the systems are actually in phase.

It will now be clear that simultaneous closure of the switches 71, 72 and 73 and energization of the operating coil 69, through which closure of the switch 68 is effected, can be produced only when the lines 66 and 67 are substantially in synchronism. The three switches 71, 72 and.7 3 may 1 of course be replaced by a single switch operable in response to the simultaneous deenergization of the switcli operating fers therefrom in that the machine 42 is utilized to drive a small alternating. cur rent machine 170 which comprises an armature winding 171 connected to slip rings 172 and a field winding 173. which is arranged to be supplied with direct current from a source 17 4; through an adjustable resistor 175; A reactor 12' similar to the reactor 12 of Fig. 1 is connected between the slip rings 172. Current is supplied to the operating coil" 52 of the switch 45 from a source 176 through an electron discharge device comprising an anode 177, a grid 17 8 and a cathode 179. H,

.In view of what has been said in connection with Fig. 6, it will be apparent that current of a frequency proportional in value to the resultant frequency of (the two sys-.

tems is supplied from the machine 17 0 to the reactor 12'. The voltage impressed on the id 178 through the reactor 12" is there- ?dre directly proportional to the resultant frequency of the two systems and closure of the switch 45 is efiected when the frequencies of the two' systems have become substantially equal. The manner in which the operation of the switch 45 of Fig. 8 may be made also responsive to the voltage and phase relations of the two sources will be apparent from the description of Fig. 6.

The embodiments of my invention illustrated and described herein have been selected for the urpose of clearly setting forth the princip es involved in accordance with the patent statutes; It will be, apparent however that many modifications ,may made in the construction andarrangement o f the apparatus to ada t it to'the conditions of difierent useful app ications and I there-.

fore aim inthe appended claims to cover all such modifications as :fall within the true spirit and scope of my invention.

' What I claim as new and desire to secure by Letters Patent of the United States, 1s:

ling the interconnection of :two sources, the combination of a plurality of electron discharge devices, a control circuit and an operating ciruit for each of said devices means arranged to control the potential oi each of said control circuits in accordance with a difierent resultant electrical condition produced, by the interaction of said sources, and means connected in said; operatin circuits for causing interconnection of Sci sources when a predetermined. relation exists between said diflerent resultant electrical conditions.

V 2, In, a synchronizing system for control 1. In a synchronizing system for control-* ling the interconnection of twosources, the

combination of a plurality of electron discharge devices, a control circuit and an opcrating circuit for each of said devices, means arranged to control the potential of one of said control circuits in accordance with the resultant frequency of said sources, means arranged to control the potential of another of said control circuits in accordance with the difference in the magnitudes ofthe voltages of said sources, means arranged to control the potential of still an-' other of said, control circuits in accordance with the phase relation of said sources, and

, means arranged to be connected-in said opcrating circuits for causing interconnection of said sources when a predetermined relation exists between the potentials of said control circuits.

3. In a synchronizing system'for controlling the interconnection of two sources, the

combination of an electron discharge device,

control and operating circuits for said device, and a reactor arranged to interconnect said sources for controlling the poten-' tial of said control circuit in accordance with a resultant electrical condition pro- .duced by said sources, and means connected in said operating circuit for interconnect mg said sources when said potential has assumed' a predetermined value.

0 4. In a synchronizing system for controlhug the interconnection of two sources, the combination. of an electrondischarge device, means including a resistor and a -reactor connected between said sources for prpducing across said reactor a voltage drop having a value dependent on the relation between the electrical conditions of said systems, a circuit connected across said reactor for controlling the operation of said device, an operating circuit arranged to be controlled by said device, and means arranged to be connected ,in said operating circuit for interconnecting said sources. I

5. In a synchronizing system for controlling the interconnection of two sources, the combination of an electron discharge device, control and operating circuits for said device, a resistor connected across said control circuit, means for rectifying the voltages of said sources andfor applying the resultant of the rectified voltages to sand resistor, a switch .for interconnecting said sources, and means arranged to be connected in said operatin circuit for controlling the o eration o saidswitch;

6. In async ronizing system for controlling the interconnection of two sources, the combination ofan electron discharge device, control and operating circuitsdor'said device, means for rectifying the voltages of said sources, means for appl 'ng the resultant of the actual and rectifi d voltages III of said sourcesto said control circuit, a

switch for interconnecting said sources, and means arranged to be connected in said operating circuit for controlling the operation of said switch.

7. In a synchronizing system for controlling the interconnection of two sources, the

combination of a plurality of electron discharge devices, a control circuit and an operating circuit for each device, a resistor and a reactor connected between said circuits for controlling the potential of one of said control circuits in accordance with the resultant frequency of said sources, means including a rectifier connected between said sources and a resistor connected across said rectifier for controllin the potential of another of said contro circuits in accordance with the difference in the magnitudes of the voltages of said sources, means comprising a rectifier connected between said sources and resistors connected across said rectifier in series with said lines for controlling the potential of still another of said control circuits in accordance with the resultant of the actual and rectified voltages of said sources, and means arranged to be connected in said operating circuits for causing interconnection of said sources when a predetermined relation exists between the potentials of said control circuits.

In witness whereof, I have hereunto set my hand.

FRIEDRICH WILHELM MEYER. 

